Dual-mono with Peavey IPR-1600

rcs · #1 11-16-2010, 03:30 PM

Hi everyone,

My QSC PLX1602 is becoming less and less reliable (even after two trips to the shop) and I've decided to replace it. I'm considering the Peavey IPR-1600 which would be used with an SWR Grand Prix preamp and one or two 4-ohm Acme Lo B-2s (depending on the volume level of the gig.)

My question is: when I'm using both cabinets can I use the Thru/Out jacks on the IPR-1600 to run in dual-mono mode? If I understand the IPR-1600 correctly I could run a 1/4"-terminated cable to connect the channel A out to the channel B in.

Or should I find a Y/splitter cable and use that to drive both inputs?

Edit: hmm, the manual says that the Thru/Out is 1/4" unbalanced tip/sleeve whereas the input is 3-pin XLR or 6.3mm, which I assume is tip/ring/sleeve. Hmmm.

ulrich · #2 11-16-2010, 03:44 PM

Y cable, jumper unused inputs - whatevs, same thing as far as your gear is concerned.

I use a 1/4 jumper to parallel mono my QSCRMX1450, because it's just easier than using the dip switches.

Unrelated note: While it is fine to Y one output to two inputs, never Y two outputs to one input.

1/4" TS on instrument cable will be perfect for the IPR. A short cable meant for patching effects pedal, would be a good choice

rcs · #3 11-18-2010, 08:54 AM

Thanks, Ulrich. I've gone ahead and ordered the IPR-1600 so I'll try (and report back) after the weekend on both approaches.

MooneyDriver · #4 11-18-2010, 09:01 AM

Why not bridge to 2 ohms? You just connect the speakers to the + on the A-channel output and the - on the B-channel output...

-Neil

ulrich · #5 11-18-2010, 10:06 AM

Quote:

Originally Posted by MooneyDriver

Why not bridge to 2 ohms? You just connect the speakers to the + on the A-channel output and the - on the B-channel output...

-Neil

Minimum impedance, when bridged, is twice regular minimum impedance. Normal min. impedance for the IPR is two ohms, so bridged it would be four ohms.

Peavey gear tends to be rugged. It might work, but I wouldn't try it.

greenboy · #6 11-18-2010, 10:16 AM

Quote:

Originally Posted by ulrich

Minimum impedance, when bridged, is twice regular minimum impedance. Normal min. impedance for the IPR is two ohms, so bridged it would be four ohms.

Peavey gear tends to be rugged. It might work, but I wouldn't try it.

Actually building a bridge cable (properly) for the IPR is Peavey approved. There's been posts here about that.

ulrich · #7 11-18-2010, 10:23 AM

Quote:

Originally Posted by greenboy

Actually building a bridge cable (properly) for the IPR is Peavey approved. There's been posts here about that.

Agreed. But, into a two ohm load?

MooneyDriver · #8 11-18-2010, 10:28 AM

Yes, the amp is designed to run at 1,000 watts into a single 2 ohm load:

http://www.peavey.com/assets/literat...01260_8659.pdf

See page 22 of the manual.

greenboy · #9 11-18-2010, 10:38 AM

Quote:

Originally Posted by ulrich

Agreed. But, into a two ohm load?

Oops, ulrich, skimming error. Missed that 2.

MooneyDriver, what you are pointing to there in the manual is a rating for driving only one channel of the amp, when the other channel is not doing anything. That has nothing to do with bridging, and you should not attempt to bridge a 2-ohm load. Like ulrich says, 4-ohm is the minimum here for bridging.

BassmanPaul · #10 11-18-2010, 10:47 AM

I'm more than a bit leery of what the manual says. In order to bridge into a 2Ω load the amp has to be stable at 1Ω per channel. I've never seen an amp that claims this outside of car audio.

greenboy · #11 11-18-2010, 10:50 AM

the manual says nothing about a 1 ohm load, Paul. See my post just above yours.

BassmanPaul · #12 11-18-2010, 11:11 AM

Quote:

Originally Posted by greenboy

the manual says nothing about a 1 ohm load, Paul. See my post just above yours.

That's my point Greenboy, the manual is unclear. It says 1x2Ω but makes no mention of bridging. As you say, that could mean power with a single channel being driven or power in bridge.

In bridge (I know you know this but others may not) half the load is seen by each amp channel. So, as an example, if an amp can put out 500W/channel @ 2Ω then in bridge you should be able to get 1000W into 4Ω. That's why I said what I posted above. The amp would have to be able to handle a 1Ω load per channel to safely bridge into 2Ω. I'd not run that amp at less than 4Ω in bridge.

greenboy · #13 11-18-2010, 11:51 AM

I've seen a fair number of amp manual spec pages that do just that: show the figure for both channels driven @ n ohms, and for when only one side is driven @ n ohms. Nothing troubling there. Does give a good indication about power supply capability.

sconix · #14 11-18-2010, 12:16 PM

If the Gran Prix pre has parallel unbalanced outs (I think it does). I'd just use 2 cables one for each channel to the PV.

BbbyBld · #15 11-18-2010, 01:26 PM

Quote:

My question is: when I'm using both cabinets can I use the Thru/Out jacks on the IPR-1600 to run in dual-mono mode? If I understand the IPR-1600 correctly I could run a 1/4"-terminated cable to connect the channel A out to the channel B in.

That's what I would do. I know the through jack is unbalanced, but we're only talking about a short patch cable here.

Don't try bridging into 2 ohms.